Harvard professor Khalil Muhammad said President Trump’s focus on law and order adds to “the longest story of America, which is a story that essentially said that this is a white European’s country, and everyone else has to play by our rules.”

NPR’s Lulu Garcia-Navarro of Weekend Edition Sunday invited the Cambridge academic on to discuss ways “white fear” is allegedly being “weaponized” in the Trump era and what can be done about it. The pair noted isolated incidents at a Philadelphia Starbucks and a golf course to buttress their points.

“Our current president ran as a law-and-order candidate, in a country with a long history where the notion of using the police as the foot soldiers of controlling African-Americans — limiting their freedom, deciding that they are indeed second-class citizens, and enforcing those laws when they were legal in this country — is a really big part of the problem,” Mr. Muhammad said, the media watchdog NewsBusters reported Tuesday. “And to evoke that mantra — to run on that mantra; to elicit the support of the entire community of professional police agencies — means that we’ve now got citizens who are playing out this policy choice — this set of politics. And that’s a big, big deal.”

The Harvard Kennedy School professor said it was difficult to quantitatively measure the veracity of his claims. Instead, he suggested viewers examine increased reporting on the issue.

“We really just can’t know for sure how much greater the problem is,” Mr. Muhammad said. “What has definitely increased is the amount of video evidence; the amount of copy — meaning what journalists are writing around these issues; and even the organizing around trying to do something about it.”

“What I’m trying to suggest here is that we’ve got to come up with some policies that raise the costs of bad behavior — of treating people differently than you would want to be treated,” he added. “And that is a problem of white fear being weaponized; and that is a problem of police officers being a little too prickly when people are upset about having been judged harshly or inappropriately.”